Lockable swivel apparatus

ABSTRACT

A swivel apparatus includes upper and lower housings having a passage therethrough operably connected with a coupling for selective relative rotation; at least one movable piston having a first position where the housings are rotationally locked to each other and a second position where the housings are free for relative rotation; the piston is retained to the upper housing with a retainer secured within and discrete from the upper housing, and the retainer is axially spaced from a bearing assembly.

FIELD OF THE INVENTION

The field of the invention is a lockable swivel that can be used in a drill string for rotation thereof when the swivel is locked and in wireline applications to let the drill string rotate freely when the wireline is operated.

BACKGROUND OF THE INVENTION

Previously, if the operator desired to rotate the drill string during wireline operations, the wireline was pulled from the well bore and the entry devices were disengaged from the drill string. The removal of the wireline could be avoided if an inline swivel was placed in the drill string between the wireline device and the rotary table. This arrangement would permit rotation to be accomplished with a wireline in place, but effectively disengaged the top-drive unit from its preferred role of providing both lifting power and rotation to the drill string.

Using prior conventional technology, the drill pipe was separated and raised high above the rig floor on each run in order to change out tools. Although the pipe can be rotated, the operator could not circulate or reciprocate the pipe during these periods. Circulation was achieved by adding a pump-in sub and another T.I.W. safety valve immediately above the existing T.I.W. valve; which, however, put the disconnect or break point between the upper T.I.W. valve and the swivel several feet above the rig floor creating a safety hazard while operating the rig tongs.

Further, since the tool strings must be stripped in and out beneath the upper assembly, a lubricator or tool protection device could not be used and all tools and explosives were brought onto the rig floor unshielded and unconfined. In the event of an inadvertent detonation of the explosive string shot or perforators, all personnel on the rig floor were totally exposed to this unnecessary life-threatening hazard.

Once rigged-up and going in the hole using conventional technology such as the Boyd side-entry sub, the wireline passed through the acute angle in the side entry sub. This caused excessive wearing of the wireline and creates sever grooving in the sub. The single rubber pack-off, which is commonly used with this system, is very susceptible to leaking and/or line gripping and stoppage during pump-down operations. The system cannot be used when working under surface pressure and with the need to utilize a grease injector and wireline blow out preventers (BOPs).

During pipe recovery operations, both right and left-hand torque must be worked down-hole using the rig tongs. This is a procedure has long been recognized to be one of the greatest safety hazards to be encountered during pipe recovery operations. When using this prior technology, pipe tongs were attached to the drill string and secured to the rig to hold torque that had been put into the drill string from the rotary table or top drive unit.

With the present invention, this torque can be maintained while continuing circulation and wireline operation.

USP RE41,759 FIG. 4 provided an apparatus which would allow the connection of various wireline devices 106 to be placed in the drill string 100 between the top drive unit 102 and the rotary table 114 of a conventional drilling rig throughout wireline operations. Such devices 106 as the Boyd Borehole Drill Pipe Continuous Side Entry or Exit Apparatus (such as described in U.S. Reissue Pat. No. 33,150) or the Top Entry Sub Arrangement (as described in U.S. Pat. No. 5,284,210) may both be utilized for various wireline operations.

Referring to FIG. 4, what this reference disclosed is a lockable in-line swivel device 110 which is selectively engaged by the operator to permit or inhibit rotational movement provided by a top drive unit 102 to be transmitted through the swivel 110 to the pipe string 112 and to allow disengagement of the locked swivel 110 so that rotation may be accomplished by the rotary table 114 simultaneously with the wireline operations.

This design permitted the wireline entry devices 106 to be left in the drill string 100 during all operations involving the wireline operation avoiding the time consuming makeup and disengagement of the entry tools 106 required to safely permit entry of the wireline into the well bore. If rotation and longitudinal movement is desired, the wireline alone was removed from the wellbore, but the entry tool 106 remained in place and the swivel 110 is locked to provide transmission of all rotation through the swivel 110 into the pipe string 112.

At other times, the operator using a top-drive unit 102 could pick up the drill string 100 and yet maintain torque which has been put into the pipe string 112 in pipe recovery operations. This was done by engaging the swivel 110 in locked position and picking up with the top drive unit 102. As the torque is worked through the drill string 100, additional wireline operations and the operator would set the drill string 100 down, disengage the swivel 110, continue to rotate with the rotary table 114 and continue the wireline operations.

The swivel provided to accomplish the above operations is shown in FIGS. 1-3 of this patent. The design features a multi-component body with spaced splines with the lower spline juxtaposed in an overlapping relation to a retainer that holds the upper housing assembly of body parts to the lower housing with fairly primitive rotary bearing design and no thrust bearing capability. The present invention improves on the shortcomings of this design providing several unique features that reduce the number of housing parts to allow the use of a unitary upper and lower body with an internal retaining ring to secure the actuating piston to the upper housing. The design adds thrust bearing capability nested between pairs of tapered surfaces on one side between the housings and on the other between the lower housing and the end cap. Spherical bearings are used to facilitate relative rotation. These and other features of the present invention will be more readily appreciated by a review of the description of the preferred embodiment and the associated drawing while recognizing that the full scope of the invention is to be found in the appended claims.

Also relevant in the lockable swivel field is U.S. Pat. No. 6,378,630 FIG. 6 where flow through the swivel compresses a stack of Belleville washers to engage splines and lock the swivel as long as flow displaces a piston to overcome the resisting spring force. Other references show swivels in general and swivels that combine a wireline entry fitting into a common housing or swivels that lock in one rotational direction and allow relative rotation in an opposite direction. Some examples of these references are U.S. Pat. Nos. 6,553,825; 5,996,712; 6,796,191; 8,171,991; 6,915,865; 6,994,628; 7,793,731; 7,316,276; 7,168,498; 7,377,316; 7,392,850; 8,210,268; 4,074,775 FIG. 2B; 7,011,162 FIGS. 2a and 2B; 4,781,359; 4,715,454 and 7,857,058.

SUMMARY OF THE INVENTION

A lockable swivel features a unitary upper housing connected to a unitary lower housing with a connector to hold the housing components together for relative or tandem rotation. A hydraulically actuated piston shifts spaced apart splines axially to selectively engage splines on both housings for the locked position and to release the splines in both housing for the unlocked position. A thrust bearing in the lower housing is disposed between two pairs of tapered surfaces with the upper pair disposed on the housings and the lower pair between the connector and the lower housing. The thrust bearing is disposed between a pair of spherical bearings with the upper radial bearing retained by the upper housing and the lower radial bearing retained by the connector. An internal ring retains the piston to the upper housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a half section half exterior view of the locking swivel in the locked piston down position; and

FIG. 2 is the view of FIG. 1 in the piston up or unlocked position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1 upper body 12 is secured to lower body 13 by end cap or connector 15. A screw or other fastener 4 retains a threaded connection 30 between the upper body 12 and the connector 15. A retainer 14 is secured at thread 32 to the upper body 12 and that threaded connection is maintained by a circlip 11. A swivel piston 19 can move down until bottoming on the retainer 14 as shown in FIG. 1 and can move axially in the opposite direction until bottoming out by essentially eliminating the volume of chamber 42 when contacting an end surface that defines that chamber. Near the upper end 36 are o-ring 22 and backup ring 25 to retain pressure in the central passage 38. A cavity 40 that varies in volume is defined between seals 22 and 23. Seal 23 and upper seal 24 define a variable volume cavity 42 into which a fitting 1, 3 is connected for communicating hydraulic pressure that enlarges cavity 42 while pushing down on piston area 44 to move the piston 19 to the FIG. 1 position where it is bottomed on the retainer ring 14. Another connection 1, 2 extends into cavity 46 which is shown in FIG. 1 in its smallest volume position. Lower seal 24 and seal 23 mounted to the retainer 14 seal this variable volume space. Adding hydraulic pressure into fittings 1, 2 and removing hydraulic pressure from fitting 1, 3 advances the piston 19 up toward and into contact with a top surface that defines chamber 42.

Piston 19 has an upper spline 48 engaged with a spline 50 on the upper body 12 in the FIG. 1 locked position. At the same time the piston 19 has a lower spline 54 that engages a mating spline 52 in the FIG. 1 position. Thus the piston 19 locks the upper housing 12 to the lower housing 13 for tandem rotation when the two spline pairs are engaged. As stated before with hydraulic pressure applied to chamber 46 and removed from chamber 42 the piston 19 rises and the spline pairs 52, 54 disengage so that the housing components 12 and 13 can relatively rotate. Spline pairs 48 and 50 remain engaged. Such relative rotation is facilitated by the upper and lower preferably spherical bearings 9 which can also include any type of rolling element bearing such as ball, roller or needle among others, that are disposed on opposite sides of the thrust bearing 8. The upper bearing 9 is externally retained by the lower end 56 of the upper body 12 on two adjacent sides that are perpendicular to each other and surfaces 60 and 62 on the lower body 13. The lower bearing is retained externally by adjacent surfaces 64 and 66 on the connector 15 and surface 68 on the lower body as well as an adjacent surface on the end cap 16 that is retained with screws 6 to the connector 15. A grease fitting 7 allows adding grease to the lower spherical bearing 9.

Thrust bearing 8 is externally retained by adjacent perpendicular surfaces 74 and 76 on the connector 15 and 70 and 72 on the lower body 13. Thrust bearing 8 is straddled by mating sloping surfaces on opposed sides. Above the bearing 8 surface 80 on the lower end 56 of the upper body 12 sits in opposition to surface 82 on the lower body. Below the bearing 8 surface 84 on the lower body 13 is opposed to mating surface 86 on the connector 15. Surfaces 84 and 86 are not intended to contact. In one option the pair of mating sloping surfaces 80 and 82 above bearing 8 can contact and in that variation the upper radial bearing 9 can be replaced with a floating roller bearing to transmit the axial component of a thrust load while the radial component is absorbed by the upper body 12.

In preferred alternative to dealing with tensile thrust, as it is very unusual to have compressive thrust loads in such devices, the surfaces 84 and 86 or 80 and 82 do not contact and the thrust load is taken by the upper spherical bearing 9. The mating pairs of sloping surfaces allow the use of a larger thrust bearing 8 than the radial bearings 9 that straddle it above and below.

The piston 19 can be pinned at 5 to allow external indication of the position of the piston 19. Piston 19 can also be shear pinned to the upper body 12 for run in to prevent accidental movement of the piston 19 until a predetermined force is applied in chamber 42.

Those skilled in the art can now appreciate several features and variations thereof as depicted in FIG. 1. FIG. 2 is identical to FIG. 1 with the piston 19 in the raised position toward a travel stop that is the top radial surface that defines chamber 42, to permit relative rotation between the bodies 12 and 13. The bodies 12 and 13 are each made of a single component. The piston 19 is retained by an internal ring 14 located near a thick portion of the upper body 12. Spaced apart spherical bearings 9 straddle an even larger thrust bearing 8. The upper splines mate adjacent a thick portion of the upper housing 12 where there are no weak points such as threaded body connections. The lower splines mate within the retainer ring 14 to lend support to the lower end of the piston 19. The bearing assembly 8, 9 is axially spaced from the meshing splines. The upper body takes a radial component from thrust loading and transfers the axial component to the thrust bearing 9.

While the piston is illustrated as hydraulically externally driven in opposed directions those skilled in the art will appreciate that the piston can be alternatively actuated with flow cycles therethrough that in combination with a j-slot mechanism can put the piston 19 in the splines locked and unlocked positions in situations where hydraulic power systems are not available. In this case the piston is acted on by a spring return to work against the force generated with fluid flow. On the other hand the piston can have unequal piston areas and can be moved against a spring bias with simply applied pressure and removal of the applied pressure.

The driving force can also be locally available rig air. The spacing of the bearing assembly that comprises bearings 8 and 9 axially spaced from the retainer 14 allow the use of larger bearings without adding unduly to the diameter of the housings while at the same time providing additional supporting wall for the bearings.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims appended hereto. 

1. A swivel apparatus, comprising: upper and lower housings having a passage therethrough operably connected with a coupling for selective relative rotation; at least one movable piston having a first position where said housings are rotationally locked to each other and a second position where said housings are free for relative rotation; wherein said piston is retained to said upper housing with a retainer secured within and discrete from said upper housing, said retainer axially spaced from a bearing assembly.
 2. The assembly of claim 1, wherein said retainer radially disposed between said piston and said upper housing when said piston is in said second position.
 3. The assembly of claim 1, wherein said bearing assembly compnses a thrust bearing.
 4. The assembly of claim 1, wherein said upper housing is a single component.
 5. The assembly of claim 1, wherein said bearing assembly comprises radial bearings on opposed sides of a thrust bearing.
 6. The assembly of claim 1, wherein said bearing assembly compnses a larger diameter thrust bearing than a pair of adjacent radial bearings.
 7. The assembly of claim 1, wherein said bearing assembly comprises rolling element bearings.
 8. The assembly of claim 1, wherein said upper and lower housings comprise splines and said piston comprises spaced splines that selectively engage both splines on said upper and lower bodies for selective rotational locking of said bodies, and said splines are axially spaced from said coupling.
 9. The assembly of claim 1, wherein: said bearing assembly comprises a thrust bearing that is disposed between a first and second pair of tapered surfaces; said first pair of tapered surfaces disposed on said upper and lower housings and said second pair of surfaces disposed on said coupling and said lower housing; and said bearing assembly further comprises a first spherical bearing on an opposite side of said first pair of tapered surfaces from said thrust bearing and a second spherical bearing on an opposite side of said second pair of tapered surfaces from said thrust bearing.
 10. The assembly of claim 1, wherein said piston is movable with flow or pressure in said passage.
 11. The assembly of claim 2, wherein said bearing assembly compnses a thrust bearing.
 12. The assembly of claim 11, wherein said bearing assembly compnses radial bearings on opposed sides of said thrust bearing.
 13. The assembly of claim 12, wherein said thrust bearing comprises a larger diameter than said radial bearings.
 14. The assembly of claim 13, wherein: said thrust bearing is disposed between a first and second pair of tapered surfaces; said first pair of tapered surfaces disposed on said upper and lower housings and said second pair of surfaces disposed on said coupling and said lower housing; and said bearing assembly further comprises a floating roller bearing on an opposite side of said first pair of tapered surfaces from said thrust bearing and a spherical bearing on an opposite side of said second pair of tapered surfaces from said thrust bearing.
 15. The assembly of claim 12, wherein said radial bearings are rolling element bearings.
 16. The assembly of claim 12, wherein said upper and lower housings comprise splines and said piston comprises spaced splines that selectively engage at least one pair of splines on said upper and lower bodies for selective rotational locking of said bodies, and said splines are axially spaced from said coupling.
 17. The assembly of claim 12, wherein said upper housing is a single component.
 18. The assembly of claim 12, wherein said piston is movable with flow or pressure in said passage.
 19. The assembly of claim 14, wherein said upper and lower housings comprise splines and said piston comprises spaced splines that selectively engage both splines on said upper and lower bodies for selective rotational locking of said bodies, and said splines are axially spaced from said coupling.
 20. The assembly of claim 19, wherein said upper housing is a single component.
 21. The assembly of claim 9, wherein said first spherical bearing takes tensile thrust load.
 22. The assembly of claim 14, wherein said first pair of tapered surfaces contacting under tensile thrust loading. 